An investigation on photoluminescence and energy transfer of Eu3+/Sm3+ single-doped and co-doped Ca4YO(BO3)3 phosphors

The present investigation aims to demonstrate the potentiality of Eu3+/Sm3+ single-doped and co-doped Ca4YO(BO3)3 phosphors, which were prepared by a sol–gel method. The X-ray diffraction (XRD) profiles showed that all the observed peaks could be attributed to the monoclinic phase of Ca4YO(BO3)3. From the measured emission profiles, we have noticed that both the single-doped Eu3+/Sm3+ phosphors shows four emission transitions of 5D0 → 7F0,1,2,3 and 4G5/2 → 6H5/2,7/2,9/2,11/2 respectively. Among them, the 5D0 → 7F2 of Eu3+ and 4G5/2 → 6H7/2 of Sm3+ are intense emission transitions, leading to an intense red color emission from the prepared phosphors. The excitation spectra showed that Eu3+/Sm3+ doped samples can be excited efficiently by 394 nm and 402 nm respectively, incidentally which matches well with the characteristic emission from UVLED. The co-doping of Sm3+ ions can broaden and strengthen the absorption of near UV region and to be efficient to sensitize the emission of the Ca4YO(BO3)3:Eu3+ phosphor. The mechanism involved in the energy transfer between Eu3+ and Sm3+ has been explained and elucidated by an energy level diagram.